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  <div class="section" id="module-unicodedata">
<span id="unicodedata-unicode-database"></span><h1>6.5. <a class="reference internal" href="#module-unicodedata" title="unicodedata: Access the Unicode Database."><code class="xref py py-mod docutils literal notranslate"><span class="pre">unicodedata</span></code></a> --- Unicode Database<a class="headerlink" href="#module-unicodedata" title="永久链接至标题">¶</a></h1>
<hr class="docutils" id="index-0" />
<p>This module provides access to the Unicode Character Database (UCD) which
defines character properties for all Unicode characters. The data contained in
this database is compiled from the <a class="reference external" href="http://www.unicode.org/Public/9.0.0/ucd">UCD version 9.0.0</a>.</p>
<p>The module uses the same names and symbols as defined by Unicode
Standard Annex #44, <a class="reference external" href="http://www.unicode.org/reports/tr44/tr44-6.html">&quot;Unicode Character Database&quot;</a>.  It defines the
following functions:</p>
<dl class="function">
<dt id="unicodedata.lookup">
<code class="descclassname">unicodedata.</code><code class="descname">lookup</code><span class="sig-paren">(</span><em>name</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.lookup" title="永久链接至目标">¶</a></dt>
<dd><p>Look up character by name.  If a character with the given name is found, return
the corresponding character.  If not found, <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> is raised.</p>
<div class="versionchanged">
<p><span class="versionmodified">在 3.3 版更改: </span>Support for name aliases <a class="footnote-reference" href="#id3" id="id1">[1]</a> and named sequences <a class="footnote-reference" href="#id4" id="id2">[2]</a> has been added.</p>
</div>
</dd></dl>

<dl class="function">
<dt id="unicodedata.name">
<code class="descclassname">unicodedata.</code><code class="descname">name</code><span class="sig-paren">(</span><em>chr</em><span class="optional">[</span>, <em>default</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.name" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the name assigned to the character <em>chr</em> as a string. If no
name is defined, <em>default</em> is returned, or, if not given, <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is
raised.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.decimal">
<code class="descclassname">unicodedata.</code><code class="descname">decimal</code><span class="sig-paren">(</span><em>chr</em><span class="optional">[</span>, <em>default</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.decimal" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the decimal value assigned to the character <em>chr</em> as integer.
If no such value is defined, <em>default</em> is returned, or, if not given,
<a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is raised.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.digit">
<code class="descclassname">unicodedata.</code><code class="descname">digit</code><span class="sig-paren">(</span><em>chr</em><span class="optional">[</span>, <em>default</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.digit" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the digit value assigned to the character <em>chr</em> as integer.
If no such value is defined, <em>default</em> is returned, or, if not given,
<a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is raised.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.numeric">
<code class="descclassname">unicodedata.</code><code class="descname">numeric</code><span class="sig-paren">(</span><em>chr</em><span class="optional">[</span>, <em>default</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.numeric" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the numeric value assigned to the character <em>chr</em> as float.
If no such value is defined, <em>default</em> is returned, or, if not given,
<a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is raised.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.category">
<code class="descclassname">unicodedata.</code><code class="descname">category</code><span class="sig-paren">(</span><em>chr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.category" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the general category assigned to the character <em>chr</em> as
string.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.bidirectional">
<code class="descclassname">unicodedata.</code><code class="descname">bidirectional</code><span class="sig-paren">(</span><em>chr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.bidirectional" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the bidirectional class assigned to the character <em>chr</em> as
string. If no such value is defined, an empty string is returned.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.combining">
<code class="descclassname">unicodedata.</code><code class="descname">combining</code><span class="sig-paren">(</span><em>chr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.combining" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the canonical combining class assigned to the character <em>chr</em>
as integer. Returns <code class="docutils literal notranslate"><span class="pre">0</span></code> if no combining class is defined.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.east_asian_width">
<code class="descclassname">unicodedata.</code><code class="descname">east_asian_width</code><span class="sig-paren">(</span><em>chr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.east_asian_width" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the east asian width assigned to the character <em>chr</em> as
string.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.mirrored">
<code class="descclassname">unicodedata.</code><code class="descname">mirrored</code><span class="sig-paren">(</span><em>chr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.mirrored" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the mirrored property assigned to the character <em>chr</em> as
integer. Returns <code class="docutils literal notranslate"><span class="pre">1</span></code> if the character has been identified as a &quot;mirrored&quot;
character in bidirectional text, <code class="docutils literal notranslate"><span class="pre">0</span></code> otherwise.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.decomposition">
<code class="descclassname">unicodedata.</code><code class="descname">decomposition</code><span class="sig-paren">(</span><em>chr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.decomposition" title="永久链接至目标">¶</a></dt>
<dd><p>Returns the character decomposition mapping assigned to the character
<em>chr</em> as string. An empty string is returned in case no such mapping is
defined.</p>
</dd></dl>

<dl class="function">
<dt id="unicodedata.normalize">
<code class="descclassname">unicodedata.</code><code class="descname">normalize</code><span class="sig-paren">(</span><em>form</em>, <em>unistr</em><span class="sig-paren">)</span><a class="headerlink" href="#unicodedata.normalize" title="永久链接至目标">¶</a></dt>
<dd><p>Return the normal form <em>form</em> for the Unicode string <em>unistr</em>. Valid values for
<em>form</em> are 'NFC', 'NFKC', 'NFD', and 'NFKD'.</p>
<p>The Unicode standard defines various normalization forms of a Unicode string,
based on the definition of canonical equivalence and compatibility equivalence.
In Unicode, several characters can be expressed in various way. For example, the
character U+00C7 (LATIN CAPITAL LETTER C WITH CEDILLA) can also be expressed as
the sequence U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING CEDILLA).</p>
<p>For each character, there are two normal forms: normal form C and normal form D.
Normal form D (NFD) is also known as canonical decomposition, and translates
each character into its decomposed form. Normal form C (NFC) first applies a
canonical decomposition, then composes pre-combined characters again.</p>
<p>In addition to these two forms, there are two additional normal forms based on
compatibility equivalence. In Unicode, certain characters are supported which
normally would be unified with other characters. For example, U+2160 (ROMAN
NUMERAL ONE) is really the same thing as U+0049 (LATIN CAPITAL LETTER I).
However, it is supported in Unicode for compatibility with existing character
sets (e.g. gb2312).</p>
<p>The normal form KD (NFKD) will apply the compatibility decomposition, i.e.
replace all compatibility characters with their equivalents. The normal form KC
(NFKC) first applies the compatibility decomposition, followed by the canonical
composition.</p>
<p>Even if two unicode strings are normalized and look the same to
a human reader, if one has combining characters and the other
doesn't, they may not compare equal.</p>
</dd></dl>

<p>In addition, the module exposes the following constant:</p>
<dl class="data">
<dt id="unicodedata.unidata_version">
<code class="descclassname">unicodedata.</code><code class="descname">unidata_version</code><a class="headerlink" href="#unicodedata.unidata_version" title="永久链接至目标">¶</a></dt>
<dd><p>The version of the Unicode database used in this module.</p>
</dd></dl>

<dl class="data">
<dt id="unicodedata.ucd_3_2_0">
<code class="descclassname">unicodedata.</code><code class="descname">ucd_3_2_0</code><a class="headerlink" href="#unicodedata.ucd_3_2_0" title="永久链接至目标">¶</a></dt>
<dd><p>This is an object that has the same methods as the entire module, but uses the
Unicode database version 3.2 instead, for applications that require this
specific version of the Unicode database (such as IDNA).</p>
</dd></dl>

<p>Examples:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="kn">import</span> <span class="nn">unicodedata</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">unicodedata</span><span class="o">.</span><span class="n">lookup</span><span class="p">(</span><span class="s1">&#39;LEFT CURLY BRACKET&#39;</span><span class="p">)</span>
<span class="go">&#39;{&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">unicodedata</span><span class="o">.</span><span class="n">name</span><span class="p">(</span><span class="s1">&#39;/&#39;</span><span class="p">)</span>
<span class="go">&#39;SOLIDUS&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">unicodedata</span><span class="o">.</span><span class="n">decimal</span><span class="p">(</span><span class="s1">&#39;9&#39;</span><span class="p">)</span>
<span class="go">9</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">unicodedata</span><span class="o">.</span><span class="n">decimal</span><span class="p">(</span><span class="s1">&#39;a&#39;</span><span class="p">)</span>
<span class="gt">Traceback (most recent call last):</span>
  File <span class="nb">&quot;&lt;stdin&gt;&quot;</span>, line <span class="m">1</span>, in <span class="n">&lt;module&gt;</span>
<span class="gr">ValueError</span>: <span class="n">not a decimal</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">unicodedata</span><span class="o">.</span><span class="n">category</span><span class="p">(</span><span class="s1">&#39;A&#39;</span><span class="p">)</span>  <span class="c1"># &#39;L&#39;etter, &#39;u&#39;ppercase</span>
<span class="go">&#39;Lu&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">unicodedata</span><span class="o">.</span><span class="n">bidirectional</span><span class="p">(</span><span class="s1">&#39;</span><span class="se">\u0660</span><span class="s1">&#39;</span><span class="p">)</span> <span class="c1"># &#39;A&#39;rabic, &#39;N&#39;umber</span>
<span class="go">&#39;AN&#39;</span>
</pre></div>
</div>
<p class="rubric">Footnotes</p>
<table class="docutils footnote" frame="void" id="id3" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id1">[1]</a></td><td><a class="reference external" href="http://www.unicode.org/Public/9.0.0/ucd/NameAliases.txt">http://www.unicode.org/Public/9.0.0/ucd/NameAliases.txt</a></td></tr>
</tbody>
</table>
<table class="docutils footnote" frame="void" id="id4" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id2">[2]</a></td><td><a class="reference external" href="http://www.unicode.org/Public/9.0.0/ucd/NamedSequences.txt">http://www.unicode.org/Public/9.0.0/ucd/NamedSequences.txt</a></td></tr>
</tbody>
</table>
</div>


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